Hello everybody,

I have a dataset where each row has number of subjects and that gives me natural weights for the variance function. Additionally I see that variance increases with Age, which is a regressor.
So using gls I have



weights=varFixed(~1/n)

but don't know how to include the extra effect of the regressor.
Fitted values show a quadratic curve vs. age, not sure if that helps.

Thanks everybody.
Stephen

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